package org.jeemp.utils;

import cn.hutool.core.date.DateUtil;
import io.jsonwebtoken.*;
import io.jsonwebtoken.io.Decoders;
import io.jsonwebtoken.security.Keys;
import lombok.extern.slf4j.Slf4j;
import org.jeemp.config.JwtSecurityProperties;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import javax.crypto.SecretKey;
import java.security.Key;
import java.util.*;
import java.util.stream.Collectors;

@Slf4j
@Component
public class JwtTokenUtils implements InitializingBean {

    private final JwtSecurityProperties jwtSecurityProperties;
    private static final String AUTHORITIES_KEY = "auth";
    private Key key;

    private static final String CLAIM_KEY_USERNAME = "sub";
    private static final String CLAIM_KEY_CREATED = "created";

    public JwtTokenUtils(JwtSecurityProperties jwtSecurityProperties) {
        this.jwtSecurityProperties = jwtSecurityProperties;
    }

    @Override
    public void afterPropertiesSet() {

        byte[] keyBytes = Decoders.BASE64.decode(jwtSecurityProperties.getBase64Secret());
        this.key = Keys.hmacShaKeyFor(keyBytes);
    }


    public  String createToken (Map<String, Object> claims) {
        return Jwts.builder()
                .claim(AUTHORITIES_KEY, claims)
                .setId(UUID.randomUUID().toString())
                .setIssuedAt(new Date())
                .setExpiration(new Date((new Date()).getTime() + jwtSecurityProperties.getTokenValidityInSeconds()))
                .compressWith(CompressionCodecs.DEFLATE)
                .signWith(key, SignatureAlgorithm.HS512)
                .compact();
    }

    public Date getExpirationDateFromToken(String token) {
        Date expiration;
        try {
            final Claims claims = getClaimsFromToken(token);
            expiration = claims.getExpiration();
        } catch (Exception e) {
            expiration = null;
        }
        return expiration;
    }

    public Authentication getAuthentication(String token) {
        Claims claims = Jwts.parser()
                .setSigningKey(key)
                .parseClaimsJws(token)
                .getBody();

        Collection<? extends GrantedAuthority> authorities =
                Arrays.stream(claims.get(AUTHORITIES_KEY).toString().split(","))
                        .map(SimpleGrantedAuthority::new)
                        .collect(Collectors.toList());

        HashMap map =(HashMap) claims.get("auth");

        User principal = new User(map.get("user").toString(), map.get("password").toString(), authorities);

        return new UsernamePasswordAuthenticationToken(principal, token, authorities);
    }

    public boolean validateToken(String authToken) {
        try {
            Jwts.parser().setSigningKey(key).parseClaimsJws(authToken);
            return true;
        } catch (io.jsonwebtoken.security.SecurityException | MalformedJwtException e) {
            log.info("Invalid JWT signature.");
            e.printStackTrace();
        } catch (ExpiredJwtException e) {
            log.info("Expired JWT token.");
            e.printStackTrace();
        } catch (UnsupportedJwtException e) {
            log.info("Unsupported JWT token.");
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            log.info("JWT token compact of handler are invalid.");
            e.printStackTrace();
        }
        return false;
    }

    private Claims getClaimsFromToken(String token) {
        Claims claims;
        try {
            claims = Jwts.parser()
                    .setSigningKey(key)
                    .parseClaimsJws(token)
                    .getBody();
        } catch (Exception e) {
            claims = null;
        }
        return claims;
    }

    /**
     * 从token中获取登录用户名
     */
    public String getUserNameFromToken(String token) {
        String username;
        try {
            Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        } catch (Exception e) {
            username = null;
        }
        return username;
    }

    /**
     * 验证token是否还有效
     *
     * @param token       客户端传入的token
     * @param userDetails 从数据库中查询出来的用户信息
     */
    public boolean validateUserToken(String token, UserDetails userDetails) {
        String username = getUserNameFromToken(token);
        return username.equals(userDetails.getUsername()) && !isTokenExpired(token);
    }

    /**
     * 判断token是否已经失效
     */
    private boolean isTokenExpired(String token) {
        Date expiredDate = getExpiredDateFromToken(token);
        return expiredDate.before(new Date());
    }

    /**
     * 从token中获取过期时间
     */
    private Date getExpiredDateFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.getExpiration();
    }


    /**
     * 根据用户信息生成token
     */
    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        claims.put(CLAIM_KEY_USERNAME, userDetails.getUsername());
        claims.put(CLAIM_KEY_CREATED, new Date());
        return generateToken(claims);
    }

    /**
     * 根据负责生成JWT的token
     */
    private String generateToken(Map<String, Object> claims) {
        SecretKey secretKey = getSecretKey();
        return Jwts.builder()
                .setClaims(claims)
                .setExpiration(generateExpirationDate())
                .signWith(secretKey)
                .compact();
    }

    /**
     * 生成token的过期时间
     */
    private Date generateExpirationDate() {
        return new Date(System.currentTimeMillis() + jwtSecurityProperties.getTokenValidityInSeconds());
    }

    private SecretKey getSecretKey() {
        byte[] encodeKey = Decoders.BASE64.decode(jwtSecurityProperties.getBase64Secret());
        return Keys.hmacShaKeyFor(encodeKey);
    }

    /**
     * 当原来的token没过期时是可以刷新的
     *
     * @param oldToken 带tokenHead的token
     */
    public String refreshHeadToken(String oldToken) {
        if (StrUtil.isEmpty(oldToken)) {
            return null;
        }
        String token = oldToken.substring(jwtSecurityProperties.getHeader().length());
        if (StrUtil.isEmpty(token)) {
            return null;
        }
        //token校验不通过
        Claims claims = getClaimsFromToken(token);
        if (claims == null) {
            return null;
        }
        //如果token已经过期，不支持刷新
        if (isTokenExpired(token)) {
            return null;
        }
        //如果token在30分钟之内刚刷新过，返回原token
        if (tokenRefreshJustBefore(token, 30 * 60)) {
            return token;
        } else {
            claims.put(CLAIM_KEY_CREATED, new Date());
            return generateToken(claims);
        }
    }

    /**
     * 判断token在指定时间内是否刚刚刷新过
     *
     * @param token 原token
     * @param time  指定时间（秒）
     */
    private boolean tokenRefreshJustBefore(String token, int time) {
        Claims claims = getClaimsFromToken(token);
        Date created = claims.get(CLAIM_KEY_CREATED, Date.class);
        Date refreshDate = new Date();
        //刷新时间在创建时间的指定时间内
        if (refreshDate.after(created) && refreshDate.before(DateUtil.offsetSecond(created, time))) {
            return true;
        }
        return false;
    }
}
